Abstract: A decision feedback equalizer (DFE) architecture uses feedback samples that are over-sampled with respect to the symbol rate. On-baud feedback samples are quantized with a slicer, while off-baud samples are linear, IIR samples. Both forward and feedback filters are fractionally-spaced, but adapted only at the baud instances.
Type:
Grant
Filed:
April 26, 2004
Date of Patent:
March 18, 2008
Assignee:
Dotcast, Inc.
Inventors:
Thomas J. Endres, Douglas Whitcomb, Christopher David Long, Wonzoo Chung
Abstract: A system for transmitting digital programming includes a program source providing digital information, circuitry for modulating the digital information onto a visual carrier modulated with analog television programming, and a visual transmitter coupled to the modulating circuitry. Using a phase modulation method, the system phase modulates the digital information onto a visual carrier, reduces the baseband frequencies of the phase modulated visual carrier, and amplitude modulates the phase-modulated video carrier onto a video signal. The amplified and encoded video signal are combined with an amplified sound signal and transmitted. Using an additive method, the system modulates the sidebands of the video carrier with the digital information and amplitude modulates the video signal onto the video carrier. The data-modulated sidebands are phase-shifted such that they will be in quadrature with the amplitude-modulated video signal.
Type:
Grant
Filed:
August 9, 2002
Date of Patent:
February 19, 2008
Assignee:
Dotcast, Inc.
Inventors:
Ted E. Hartson, Robert V. C. Dickinson, Walter S. Ciciora
Abstract: The present invention uses a novel adaptive soft decision device in order to jointly optimize decision device and DFE operation. The soft decision device receives the input and output samples of the slicer and generates a feedback sample by non-linearly combining them with respect to a single decision reference parameter. Moreover, the soft decision device provides novel error terms used to adapt equalizer coefficients in order to jointly optimize decision device and equalizer coefficients.
Type:
Grant
Filed:
December 20, 2002
Date of Patent:
February 20, 2007
Assignee:
Dotcast, Inc.
Inventors:
Wonzoo Chung, Thomas J. Endres, Christopher D. Long
Abstract: According to some aspects of this invention, a compact, broadband active receiving antenna uses one or more high transconductance transistors such as Field Effect Transistor(s) paired with another Transistor and arranged in a Cascode amplifier configuration. Some embodiments involve a single high transconductance transistor arranged with a high efficiency transformer in a nondissipative feedback loop to improve linearity and dynamic range. The devices have a high input resistance, low input capacitance, low noise and a very high second and third order Intercept Point. Since the gain is primarily a function of the amplifying electronics, it is not necessary to increase the directivity of the antenna to achieve higher gain.
Type:
Grant
Filed:
October 3, 2002
Date of Patent:
July 12, 2005
Assignee:
Dotcast, Inc.
Inventors:
Andrew Rowser, Christopher David Long, Glenn Borland